Sewing machine looper mechanism



Aug. 16, 1960 C. W. JOHNSON SEWING MACHINE LOOPER MECHANISM OriginalFiled May 7, 1956 2 Sheets-Sheet l FlG.l

J6 INVENTOR CARL W. JOHNSON 5% BY Z ATT NEY Aug. 16, 1960 c. w. JOHNSONSEWING MACHINE LOOPER MECHANISM 2 Sheets-Sheet 2 Original Filed May '7,1956 FIG. 2

INVENTOR CARL W. JOHNSON 225v fir'roa EY Unite SEWING MACHINE LOOPERMECHANISM Original application May 7, 1956, Ser. No. 583,027,

now Patent No. 2,900,939, dated Aug. 25, 1959. Divided and thisapplication Jan. 20, 1958, Ser. No.

12 Claims. (Cl. 112-471) The invention relates to sewing machines andmore particularly to short thread sewing machines which utilize a doublepointed needle having an eye located between the points, and wherein theopposite ends of the needle are grasped alternately by the jaws ofopposed needle bars in order to move the needle and thread back andforth through the work in forming stitches.

A machine of the type described above has many uses in the manufactureof articles of clothing such as gloves, mens and womens apparel andnovelty collars. In stitching certain types of articles, such forexample as collars of mens shirts. it is desirable that the short threadused in the machine be of such a length that the entire collar can bestitched without the necessity of piecing the thread. Otherwise, if itis necessary to piece the thread, which heretofore has required the useof a second thread to continue the formation of stitches, the piecingmay show and an unsatisfactory finished product result.

The present invention makes it unnecessary to rethread the needle duringthe stitching of certain articles, such for example as collars of mensshirts. With the mechanism embodying the invention, a much greaterlength of thread can be used than was possible in machines availableheretofore. The invention therefore results in the production of moresatisfactory products and a substantial reduction in time formerlyrequired for rethreading of needles, and stopping and starting ofstitching operations because of the need for replacing and piecing thethread.

The invention is characterized by the provision of a sewing machineprovided with a novel thread pulling mechanism or looper which pulls theloose end of a short thread through the work with great rapidity,thereby making it possible to use a thread of substantially increasedlength than heretofore was possible in the art.

It is an object of the invention to provide a novel thread pulling orlooper mechanism for use in a short thread sewing machine wherein theconstruction and operation of the mechanism is such that it is possibleto use a much longer thread and thereby improve the appearance of thework and decrease costs because of the substantial reduction in timerequired to rethread the needle and restart the operation of the machinesubsequent to the rethreading.

7 It is also an object of the invention to provide a novel threadhandling mechanism including a two revolution thread puller or looperoperative to so handle a length of thread that a substantially increasedlength of thread can be used in the machine.

With these and other objects not specifically mentioned in view, theinvention consists in certain combinations and constructions which willbe hereinafter fully described, and then set forth in the claimshereunto ap pended.

In the accompanying drawings which form a part of this specification,and in which like characters of reference indicate the same or likeparts:

a Fig. 1 is a sectional side elevation of an under and States Patent e.QCF

over stitch sewing machine provided with a preferred form of looperoperating mechanism embodying the invention, and

Fig. 2 is a partial front elevation of the mechanism shown in Fig. 1.

This application is a division of my copending application, Serial No.583,027, filed May 7,1956, now Patent No. 2,900,939, issued Aug. 25,1959 Referring to the drawings, there is disclosed apparatus constructedin accordance with the invention, and embodied in a sewing machine whichmay be similar in construction and operation to that illustrated anddescribed in Johnson Patent 2,386,800, granted October 16, 1945.

The sewing machine is driven through a belt 10 running on pulley 12secured to hub 14 of gear 16 rotatably supported on a headed stud 18attached by suitable screws 22 to the machine frame 20. Belt 10 isdriven by a pulley (not shown) which is integral with a suitable clutchmechanism (not shown) driven from a motor (not shown) in a mannersimilar to that disclosed in Patent No. 2,368,066 issued to C. W.Johnson January 23, 1945. Since the drive, as well as the mechanism foroperating the clutch and brake form no part of the present invention,further showing and description thereof are omitted.

'A cam 24 preferably formed integrally with pulley 12 is provided with acam track 26 in which run cam rollers 28 and 30 positioned atdiametrically opposite points of cam 24. Cam roller 28 is pivotallyattached to a cam lever 32 projecting from the rear end of an elongatedhub or sleeve 34 pivotally mounted on horizontal shaft 36 held at oneend by a suitable bearing bracket 38 and at the other end by anothersuitable bearing lug 40. Cam roller 30 is pivotally attached to a camlever 42 which projects rearwardly from an end of an elongated hub orsleeve 44 loosely supported on a suitably mounted horizontal shaft 46.

The machine is provided with an upper needle bar 48 and a lower needlebar 50, both vertically positioned and arranged in axial alignment. Eachneedle bar carries an actuating member 52 and 54 respectively. Actuatingmember 52 of the upper needle bar 48 engages with a shoe or roller 56pivotally mounted on an actuating arm 58 projecting from the forward endof sleeve 34. Actuating member 54 of the lower needle bar 50 engageswith a roller 60 pivotally attached to the free end of an actuating arm6'2 projecting from the forward end of sleeve 44. Since the actuatingmembers 52 and 54 of the upper and lower needle bars, respectively, areof the sliding block type, oscillating motion imparted to actuating arms58 and 62 and sleeve members 34 and 44 by cam 24 through cam levers 32and 42, respectively, is converted into vertical reciprocating motion ofneedle bars 48 and 50 which are guided in suitable bushings in guidelugs 64 and 66, respectively.

Needle N, which is moved back and forth through the work by needle bars48 and 50, is provided with a pointat each end and an eye through whichthe thread passes, located preferably about midway therebetween. Sinceboth needle bars 48 and 50 are constructed in the same manner as theneedle bars shown and described in Patent 2,386,800, a detaileddescription thereof is deemed unnecessary and is omitted in the presentcase. understood by those skilled in the art that in this type ofmachine, needle N is grasped alternately by the jaws of each needle baras the needle is pushed vertically downward or upward through the workof material M (Fig. 2).

on its upper free end carries a thread engaging head 72 It will be somounted that it may rotate around the periphery of a stationary threaddrum 74 which is suitably secured to a frame portion of the machine. Thechief function of the thread puller is to engage with its head '72 theloop L of the thread on alternate movements of the needle N and pull theloose end of the thread through the work or material over upper looper75 movably mounted above the work supporting table T (Fig. 2), anddispose it about the periphery of the drum 74 in such a manner that thedanger of snarling, fouling or breaking the thread is practicallyeliminated. Thread puller head '72, upper looper 75, the work feedingmeans (not shown), and drum 74 are similar in construction and operationto those shown in Johnson Patent 2,368,066, and since they form nospecific part of the invention, further detailed showing and descriptionthereof are omitted.

Since the loose end of the thread has to be pulled through the work anddeposited upon drum 74 before the needle N can be pushed upwardly againthrough the work by the lower needle bar, the length of the thread thatcan be used is determined by the speed with which the above mentionedloose end can be pulled through the work by the thread puller.

Figs. 1 and 2 disclose a stitching machine provided with a preferredembodiment of thread puller or looper 68 and operating mechanismtherefor. Thread puller 68 is revolved about drum 74 twice during onecycle of the machine, instead of only once, as in the machine disclosedin the above referred to Johnson patents. Due to the number ofrevolutions of thread puller 63, a substantially longer length of threadcan be used because of the novel manner in which the loose end is pulledthrough the work and disposed on drum 74 out of the path of travel ofneedle N.

In order to avoid interference with the upward moving lower needle bar50 as thread puller 68 passes the latter during its second revolution,means are provided to move thread puller 68 laterally during a portionof its revolving movement to prevent such undesirable interference.

Thread puller arm 70, shown in Figs. 1 and 2, is mounted on one end of ahorizontal shaft 76, to the other end of which is secured a gear 78.Shaft 76 also carries a sleeve member 80 loosely mounted thereon andextending from the face of the hub of arm 70 to the face of the hub ofgear 78 (Fig. l). Sleeve member 30 in turn is slidingly supported by asuitable bearing bracket 82 secured to a frame portion of the machine.The comparatively narrow gear 78, which is mounted on and rotates shaft76, meshes with a wide gear 84 loosely mounted on horizontal stud shaft36 mounted on a suitable frame portion of the machine. Gear 64 alsomeshes with and is driven by gear 88 loosely mounted on stud shaft 90mounted on a suitable frame portion of the machine. Gear 88 preferablyis integral with a gear 92 and 94, the latter of which through asuitable gear train 96, is connected with and driven by gear 16mentioned heretofore. By means of the gear arrangement illustrated, gear78 and shaft 76 are rotated two revolutions for each single revolutionof gear 88.

The lateral displacement of arm 70 for the purposes described, isaccomplished by means of a cam lever 98. The upper free end of lever 98is pivotally attached to one end of sleeve member 80 while the lower endof cam lever 98 is loosely supported on stud held by bracket 102.attached to a frame portion of the machine. Cam lever 98 carries a camroller 104 which runs in a track 105 in a suitable cam 106 formedintegrally with the hub of gear 8- which, as mentioned above, drivesgear 78 on the shaft 76 which carries thread puller arm 70. It will beseen that every time cam roller 104 runs on the high portion 167 of camtrack 105, cam lever 98 moves the sleeve member in a horizontaldirection to the left, as viewed in Fig. l, which in turn also effects alateral displacement of the shaft 76 and consequently a movement of thethread puller arm 70 away from needle bar 4 50. For better dynamicbalance, the arm 70 is provided with a counter-balance arm 108.

In a short stitch sewing machine provided with thread pullers or loopersconstruction in accordance with the invention, it is possible to use athread having a length up to twenty percent (20%) greater than has beenpossible heretofore in the art. It will be seen, therefore, that theinvention contributes not only to improved appearance in goods stitchedon a machine provided with the invention, but also the machine can beoperated for longer periods of time without rethreading.

What I claim is:

1. In a sewing machine, the combination with a needle and opposed needlebars, of means for alternately connecting said needle with said bars andprojecting said needle with a thread having a fixed end and a loose endthrough work to be stitched, a drum located adjacent one of said bars, athread puller device co-operating with said drum to pull the loose endof said thread through the work and lay it on said drum, driving meansfor operating said needle bars at a predetermined normal cyclical rateof speed, and mechanism for rotating said thread puller, said mechanismincluding means for revolving said thread puller through a plurality ofrevolutions during each thread pulling operation, whereby the loose endof said thread is pulled rapidly through said work and disposed on saiddrum.

2. In a sewing machine, a work support table, needle operating mechanismfor passing a double pointed needle having an eye located between itspoints back and forth through work moved over said support table, meansfor supporting a portion of a length of thread having a loose end andthreaded through the eye of said needle above said work, a threadsupport surface, a thread puller for engaging loops formed in saidthread below said work and for pulling the loose end of said threadthrough said work and laying it on said support surface, a shaftsupporting said thread puller, means for operating said needle operatingmechanism, and mechanism for rotating said shaft, said mechanismincluding means for rotating said thread puller through two revolutionssubsequent to its engagement with each loop of thread whereby said looseend of said thread is pulled rapidly through said work and disposed onsaid support surface.

3. In a sewing machine, a work support table, needle operating mechanismfor passing a double pointed needle having an eye located between itspoints back and forth through work moved over said support table, meansfor supporting a portion of a length of thread having a loose end andthreaded through the eye of said needle above said work, a threadsupport surface, a thread puller for engaging loops formed in saidthread below said work and for pulling the loose end of said threadthrough said work and laying it on said support table, a shaftsupporting said thread puller, means for operating said needle operatingmechanism, means for rotating said shaft at a rate of speed to travelthrough two revolutions subsequent to its engagement with each loop ofthread, and means for moving said thread puller laterally during aportion of each two revolution travel thereof for preventing itsstriking said needle operating mechanism.

4. In a sewing machine, the combination with a needle and opposed upperand lower needle bars, of means for alternately connecting said needlewith said bars and projecting said needle with a relatively long lengthof thread having a fixed end and a loose end through work to bestitched, a work support table, a thread receiving surface locatedbeneath said table and adjacent one of said bars, a rotatable threadpuller device located beneath said table and cooperating with saidsurface to engage a loop of thread formed by the upward movement of saidlower needle bar and pull the loose end of said thread through the workand lay it on said surface, driving means for operating said needle barsin a predetermined normal cyclical rate of speed, and mechanism forrotating said thrgad puller about said surface, said mechanism includingmeans for rotating said thread puller through two revolutions for eachupward movement of said lower needle bar, whereby said loose end of saidthread is pulled rapidly through said work and disposed on said drum.

5. The invention defined in claim 4 wherein mechanism is provided fordisplacing said thread puller laterally relative to said lower needlebar to prevent its striking said lower needle bar as said thread pullertravels, through its second revolution.

6. The invention defined in claim 5 wherein said mechanism includes ashifting lever, means connecting said lever .to said thread puller, acam fol-lower on said lever and a cam engaged by said cam follower fordisplacing said thread puller.

7. The invention defined in claim 4 including a movable mount for saidthread puller, and means for moving said mount to displace said threadpuller laterally out of the path of said lower needle bar as said threadpuller moves into the range of operation of said lower needle bar on itssecond revolution.

8. In a sewing machine, the combination with a needle and opposed upperand lower needle bars, of means for alternately connecting said needlewith said bars and projecting said needle with a relatively long lengthof thread having a fixed end and a loose end through work to bestitched, a work support table, a thread receiving surface locatedbeneath said table and adjacent one of said bars, a movable threadsupporting device located adjacent said upper needle bar, a rotatablethread puller device located beneath said table and cooperating withsaid surface to engage a loop of thread formed by the upward movement ofsaid lower needle bar and pull the loose end of said thread over saidthread supporting device, through the work and lay it on said surface,driving means for operating said needle bars in a predetermined normalcyclical rate of speed, and mechanism for rotating-said thread pullerabout said surface, said mechanism including means for rotating saidthread puller through two revolutions for each upward movement of saidlower needle bar, whereby said loose end of said thread is gulledrapidly through said work and disposed on said rum.

9. In a sewing machine, the combination with a needle and opposed upperand lower needle bars, of means for alternately connecting said needlewith said bars and projecting said needle with a relatively long lengthof thread having a fixed end and a loose end through work to bestitched, a work support table, a thread receiving surface locatedbeneath said table and adjacent one of said bars, a movable threadsupporting device located adjacent said upper needle bar, a rotatablethread puller device located beneath said table and cooperating withsaid surface to engage a loop of thread formed by the upward movement ofsaid lower needle bar and pull the loose end of said thread over saidthread supporting device, through the work and lay it on said surface,driving means for operating said needle bars in a predetermined normalcyclical rate of speed, means for rotating said thread puller about saidsurface through two revolutions for each upward movement of said lowerneedle bar, whereby said loose end of said thread is pulled rapidlythrough said work and disposed on said drum, and means for moving saidthread puller away from said lower needle bar as it approaches and movespast said lower needle bar on each second revolution of movement.

10. In a sewing machine, a work support table, needle operatingmechanism including an upper needle bar and an axially aligned lowerneedle bar for passing a double pointed needle having an eye locatedbetween its points back and forth through work moved over said supporttable, means for supporting a portion of a length of thread having aloose end and threaded through the eye of said needle above said work, athread supporting surface, a thread puller for engaging loops formed insaid thread below said work by the upward movement of said lower needlebar and for pulling the loose end of said thread through said work andlaying it on said support table, a shaft supporting said thread puller,means for operating said needle operating mechanism, means for rotatingsaid shaft at a rate of speed in excess of the speed of operation ofsaid needle operating mechanism for at least a part of its movementwhereby said loose end of said thread is pulled rapidly through saidwork and disposed on said surface, and means for moving said threadpuller laterally out of the path of movement of said lower needle barduring a part of the travel of said thread puller in laying said looseend of said thread on said surface.

11. In a sewing machine, a work support table, needle operatingmechanism including an upper needle bar and an axially aligned lowerneedle bar for passing a double pointed needle having an eye locatedbetween its points back and forth through work moved over said supporttable, means for supporting a portion of a length of thread having aloose end and threaded through the eye of said needle above said work, athread supporting surface, a thread puller for engaging loops formed insaid thread below said work by the upward movement of said lower needlebar and for pulling the loose end of said thread through said work andlaying it on said support table, a shaft supporting said thread puller,means for operating said needle operating mechanism, means for rotatingsaid shaft at a rate of speed in excess of the speed of operation ofsaid needle operating mechanism for at least a part of its movementwhereby said loose end of said thread is pulled rapidly through saidwork and disposed on said surface, and means for eifecting relativelateral movement between said thread puller and said lower needle bar assaid thread puller approaches and moves past said lower needle barduring a portion of the movement of said thread puller in pulling saidloose end of said thread through said work, whereby said thread pullermay dispose said loose end of said thread on said drum without strikingsaid lower needle bar.

12. In a sewing machine, a work support table, needle operatingmechanism for passing a double pointed needle having an eye locatedbetween its points back and forth through work moved over said supporttable, means for supporting a portion of a length of thread having aloose end and threaded through the eye of said needle above said work, athread support surface, a thread puller for engaging loops formed insaid thread below said work and for pulling the loose end of said threadthrough said work and laying it on said support surface, a shaftsupporting said thread puller, means for operating said needle operatingmechanism, means for rotating said shaft at a rate of speed to travelthrough two revolutions subsequent to its engagement with each loop ofthread, and means for moving said thread puller along a different pathof travel relative to said support surface during a portion of each tworevolution travel thereof for preventing its striking said needleoperating mechanism.

References Cited in the file of this patent UNITED STATES PATENTS515,713 Miller Feb. 27, 1894 1,786,621 Lawson Dec. 30, 1930 2,386,800Johnson Oct. 16, 1945

